Serial assessments of measurable (or minimal) residual disease (MRD) by qPCR may identify nascent relapse in children with acute myeloid leukaemia (AML) and enable pre‐emptive therapy. We investigated the kinetics and prognostic impact of recurrent fusion transcripts (RUNX1‐RUNX1T1, CBFB‐MYH11, KMT2A‐MLLT3 or KMT2A‐ELL ) in 774 post‐induction samples from bone marrow (BM, 347) and peripheral blood (PB, 427) from 75 children with AML. BM MRD persistence during consolidation did not increase the risk of relapse, and MRD at therapy completion did not correlate to outcome (HR = 0·64/MRD log reduction (CI: 0·32–1·26), P  = 0·19). In contrast, 8/8 patients with detectable MRD in PB after first consolidation relapsed. Persistence (n  = 4) and shifting from negative to positive (n  = 10) in PB during follow‐up predicted relapse in 14/14 patients. All 253 PB samples collected during follow‐up from 36 patients in continuous complete remission were MRD negative. In core‐binding factor AML, persistent low‐level MRD positivity in BM during follow‐up was frequent but an increment to above 5 × 10⁻⁴ heralded subsequent haematological relapse in 12/12 patients. We demonstrate that MRD monitoring in PB after induction therapy is highly informative and propose an MRD increment above 5 × 10⁻⁴ in PB and BM as a definition of molecular relapse since it always leads to haematological relapse.

中文翻译：

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通过qPCR对外周血进行可测量的残留疾病评估是儿童急性髓性白血病的疾病监测信息工具。

通过qPCR对可测量的（或最小的）残留疾病（MRD）进行连续评估，可以确定急性髓细胞性白血病（AML）儿童的新生复发，并能进行先发制人的治疗。我们调查了774份来自骨髓（BM，347）和外周血（PB，427）的诱导后样本中的重复融合转录本（RUNX1-RUNX1T1，CBFB-MYH11，KMT2A-MLLT3或KMT2A-ELL）的动力学和预后影响来自75名患有AML的儿童。巩固期间的BM MRD持续性并没有增加复发的风险，并且治疗完成时的MRD与结局无关（HR = 0·64 / MRD对数减少（CI：0·32–1·26），P  = 0·19 ）。相比之下，首次合并后8/8例可检测到MR的PB患者复发。持久性（ñ = 4）， 在14/14例患者的预测复发期间，PB从阴性转变为阳性（n = 10）。随访期间从连续完整缓解的36例患者中收集的全部253 PB样品均为MRD阴性。在核心结合因子AML中，随访期间BM的持续低水平MRD阳性很常见，但增加至5×10 ^-4以上预示着随后的血液学复发（12/12）。我们证明诱导治疗后PB中的MRD监测是非常有用的，并提出了PB和BM中MRD增加超过5×10 ^-4作为分子复发的定义，因为它总是导致血液学复发。